Extremely disappointed with the mileage

We have been extremely disappointed with the mileage of our new Trax Cruiser. Even though it carries less passengers than our past models, it has been giving us only 9-10 kmpl, whereas our 2012 model Cruiser was giving us around 10 kmpl. The vehicle has already run over 12,000 kms and yet the mileage has not improved. We understand that long life and good mileage is essential for taxi owners like us, and so we are worried that if the problem does not get resolved after the next service, we may not be able to afford to keep this vehicle.